| Message ID | 13e8abe52a18c4e46ce497ff299774700cd7e1d0.1418970310.git.osandov@osandov.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Dec 18, 2014 at 10:29:18PM -0800, Omar Sandoval wrote: > Most filesystems prevent truncation of an active swapfile by way of > inode_newsize_ok, called from inode_change_ok. NFS doesn't call either > from nfs_setattr, presumably because most of these checks are expected > to be done server-side. However, the IS_SWAPFILE check can only be done > client-side, and not doing so is dangerous. > > Signed-off-by: Omar Sandoval <osandov@osandov.com> > --- > fs/nfs/inode.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c > index 4bffe63..9205513 100644 > --- a/fs/nfs/inode.c > +++ b/fs/nfs/inode.c > @@ -506,10 +506,15 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr) > attr->ia_valid &= ~ATTR_MODE; > > if (attr->ia_valid & ATTR_SIZE) { > + loff_t i_size; > + > BUG_ON(!S_ISREG(inode->i_mode)); > > - if (attr->ia_size == i_size_read(inode)) > + i_size = i_size_read(inode); > + if (attr->ia_size == i_size) > attr->ia_valid &= ~ATTR_SIZE; > + else if (attr->ia_size < i_size && IS_SWAPFILE(inode)) > + return -ETXTBSY; > } > > /* Optimization: if the end result is no change, don't RPC */ > -- > 2.2.0 > Sorry, forgot to mention that this applies to Linus' tree as of today.
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 4bffe63..9205513 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -506,10 +506,15 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr) attr->ia_valid &= ~ATTR_MODE; if (attr->ia_valid & ATTR_SIZE) { + loff_t i_size; + BUG_ON(!S_ISREG(inode->i_mode)); - if (attr->ia_size == i_size_read(inode)) + i_size = i_size_read(inode); + if (attr->ia_size == i_size) attr->ia_valid &= ~ATTR_SIZE; + else if (attr->ia_size < i_size && IS_SWAPFILE(inode)) + return -ETXTBSY; } /* Optimization: if the end result is no change, don't RPC */
Most filesystems prevent truncation of an active swapfile by way of inode_newsize_ok, called from inode_change_ok. NFS doesn't call either from nfs_setattr, presumably because most of these checks are expected to be done server-side. However, the IS_SWAPFILE check can only be done client-side, and not doing so is dangerous. Signed-off-by: Omar Sandoval <osandov@osandov.com> --- fs/nfs/inode.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)